Quantum Dot Doped Ferroelectric Liquid Crystal System: Investigation of Electro-Optical Parameters and Relaxation Behavior

Abstract

The effect of QDs on the dielectric and electro-optical (E-O) properties of different ferroelectric liquid crystal matrices has been studied in the SmC * phase. A substantial change in the different parameters like tilt angle, spontaneous polarization and relative permittivity has been observed for the doped system. For the better understanding of the effect of QDs on FLC relaxation process another quantum dot CdSe has been dispersed in two other FLC systems 16/100 and DOBAMBC. The effect of QDs on the three FLC systems on relaxation behavior attributes to the alteration of tilt angle in different way in different doped system. This difference in relaxation behavior is observed due to the dissimilar composition and structure of FLC mixture and FLC molecule.

Recent advances on semiconducting nanomaterials–ferroelectric liquid crystals nanocomposites

“…Reprinted from [63], with the permission of AIP Publishing. ultrasonication of the mixtures at temperatures, well above their isotropic transition temperature [38,39,[54][55][56][57][58][59][60][61][62][63].…”

“…The impact of SNMs on phase transition temperatures of FLCs can also be probed through dielectric spectroscopy. Under this framework, Gupta et al [59] investigated the impact of two different semiconducting QDs i.e., Cd 1−x Zn x S/ZnS (QD1, ∼8.7 nm) and CdSe (QD2, ∼3.5 nm) on dielectric features of three distinct FLCs (Felix 17/000, Felix 16/00 and DOBAMBC). The mixing of QD1 was done with FLC (Felix 17/000).…”

“…Therefore, it becomes essential to monitor the impact of NMs on FLC parameters to optimize their concentrations and suitability for a given FLC system. More interestingly, SNMs have also been found to be capable of modifying the material parameters of host FLCs and the modifications are found to be dependent on concentration of dopant SNMs [35,38,53,59,[61][62][63][64][65]. Gupta et al [57] observed that the value of the tilt angle decreases on addition of 1 wt% CdSe QDs (∼3.5 nm) into FLC material (DOBAMBC) and assigned this decrease to the interaction between FLC molecules and CdSe QDs as: the QDs exhibit charge storing phenomenon, the transfer of charge from the dipolar group of FLC molecule to the surface of QDs produce electron donor-acceptor interaction that disturbs helical pattern of the neat FLC to give lower tilt values (figure 11(a)).…”

“…Gupta et al [57] observed that the value of the tilt angle decreases on addition of 1 wt% CdSe QDs (∼3.5 nm) into FLC material (DOBAMBC) and assigned this decrease to the interaction between FLC molecules and CdSe QDs as: the QDs exhibit charge storing phenomenon, the transfer of charge from the dipolar group of FLC molecule to the surface of QDs produce electron donor-acceptor interaction that disturbs helical pattern of the neat FLC to give lower tilt values (figure 11(a)). In another study, Gupta et al [59] measured the temperature-dependent tilt angle of neat FLC (Felix 17/000) and Cd 1−x Zn x S/ZnS QDs (∼8.7 nm) dispersed FLC nanocomposites. The magnitude of tilt angle for nanocomposite was observed to be lower in comparison to that of its pure counterpart and remained lower for the whole SmC * phase on increasing the temperature (figure 11(b)).…”

Modifications of EHPDB Physical Properties through Doping with Fe2O3 Nanoparticles (Part II)

“…3.5 nm, 1.0 wt %), and it was found that the tilt angle was smaller by about 8° (as an attraction effect between quantum dots surrounding the molecules), and P s decreased (as the secondary order parameter coupling with the tilt angle) for the doped Felix 17/000. Moreover, a new relaxation process around 10 5 Hz was revealed for the doped Felix 16/100 [ 27 ]. Das et al, after addition of Au nanoparticles (ca.…”